<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    * {
      margin: 0;
      padding: 0;
    }
    body {
      display: flex;
      justify-content: center;
      align-items: center;
      min-height: 100vh;
      background: #000;
    }
    .main {
      display:flex;
    }
    .main span {
      margin: 0 5px;
      width: 10px;
      height: 10px;
      background-color: #81ecec;
      border-radius: 50%;
      animation: wave 1s linear infinite;
    }
    .main span:nth-child(2) {
      animation-delay: 0.05s;
    }
    .main span:nth-child(3) {
      animation-delay: 0.1s;
    }
    .main span:nth-child(4) {
      animation-delay: 0.15s;
    }
    @keyframes wave {
      0% {
        transform: translateY(0);
      }
      24% {
        transform: translateY(10px);
      }
      26% {
        transform: translateY(10px);
      }
      50% {
        transform: translateY(0);
      }
      74% {
        transform: translateY(-10px);
      } 
      76% {
        transform: translateY(-10px);
      } 
      100% {
        transform: translateY(0);
      }
    }
  </style>
</head>
<body>
  <div class="main">
    <span></span>
    <span></span>
    <span></span>
    <span></span>
  </div>
</body>
</html>